Multiple expansion steam engine



' 0a; 23, 1951 Y H. G. MUELLER 2,572,652

MULTIPLE EXPANSION STEAM ENGINE Filed Feb. 21, 1947 s Sheets-Sheet 1INVENTOR V HcRMAN G MUELLER 77 1 BY TMZ ATTORNEY Oct. 23, 1951 FiledFeb. 21, 1947 H. G. MUELLER MULTIPLE EXPANSION STEAM ENGINE 6Sheets-Sheet 2 INVENTOR HERMAN GMuELLEA ATTORNEY Oct. 23, 1951 H. G.MUELLER 2,572,652

MULTIPLE EXPANSION STEAM ENGINE Fil ed Feb. 21, 1947 s Sheets-Sheet sINVENTOR 'HfRMA/V G. IWE/ELL- Z MXW ATTO R N EY Oct. 23, 1951 H. G.MUELLER MULTIPLE EXPANSION STEAM ENGINE Filed Feb. 21,- 1947 eSheets-Sheet 4 lNVENTOR 4- HJEMAA/ G. MqELLE/t BY I u ATTORNEY Oct. 23,1951 H. G. MUELLER MULTIPLE EXPANSION STEAM ENGINE 6 Sheets-Sheet 5Filed Feb. 21, 1947 INVENTOR WEWMAA G fife/L612 BY I 0 ATTORNEY Oct. 23,1951 Filed Feb. 21, 1947 v H. G. MUELLER 2,572,652

MULTIPLE EXPANSION STEAM ENGINE I 6 Sheets-Sheet 6 INVENTOR HERMANGMUELLF ATTORN EY Patented Oct. 23, 1951 UNITED STATES PATENT OFFICEMULTIPLE EXPANSION STEAM ENGINE Herman G. Mueller, Erie, Pa., assignor,by mesne assignments, to Skinner Engine 00., Pittsburgh, Pa., acorporation of Pennsylvania This invention relates generally tomulticylinder vertical compound steam engines using a Woolf steam cycle,and it relates more particularly to steeple-compound, uniflow,poppetvalve, reversing stationary and marine steam engines, on whichmuch higher steam temperatures can be used with resulting lower steamconsumption.

The steam engines now in use, Whether of the simple ormultiple-expansion type, are generally limited to maximum steamtemperatures of 600-650 F., because the walls and the piston rings ofthe cylinders, into which steam of these limited temperatures isadmitted, cannot be satisfactorily lubricated with steam at highertemperatures. Also, in marin applications, the amount of cylinder oilwhich may be used is limited, due to the condition that this oil iscarried in a highly emulsified condition by the exhaust steam to thesurface condenser, where the steam is condensed to waterall of which ispumped back to the boilers for boiler feedwater. The contamination ofthis boiler feedwater with emulsified oil becomes a serious problem,since oil on the heating surfaces of the boiler, where it accumulates,causes serious trouble and overheating. Thus, marine steam enginecylinders have always been sparingly lubricated, and, in addition, steamtemperatures have been quite limited and the trend has been to steamturbines, which require no internal lubrication, and can utilize highersteam temperatures.

Many compound tripleand quadruple-expansion marine steam engines arestill in service, running with saturated or moderately superheated.steam, and most of these engines have slide valves, and a few moremodern engines have poppet valves with steam temperatures up to about600 F. The fuel consumption per horsepower is high compared with modernturbines using higher steam pressures and temperatures. It is,therefore, a prime objective of this invention to provide new steamcylinders to replace existing steam cylinders of any conventionalarrangement, such as 2 or 4-cylinder compound engines, 3 or l-cylindertriple-expansion engines, and 4 or 5-cylinder quadruple-expansionengines, and which can be adapted to any number of cranks with any crankrelationship, and which can safely be lubricated with steam of highersuperheat and temperature, and pressures, when available, and which willreduce the steam and fuel consumption of the main engine as much as 30to 40%.

With such a conversion, only the main cylin- Application February 21,1947, Serial No. 730,114

Claims. (01. 121-102) ders are replaced, and the new cylinders are builtto fit existing columns, frames and bases, using these parts intact,together with the existing crankshaft, connecting rods and cross-.heads, and using the existing conventional Stephenson linkage valve gearand the existing reversing jack and controls to actuate, by means ofrocking earns, the poppet valves mounted in the cylinder heads of thenew cylinder assemblies.

Old boilers may be utilized at their existing steam pressure with mynovel cylinders by adding superheaters thereto to-raise the steamtemperature to 750-800 F. or more, thereby greatly reducing the steamand fuel consumption. In some cases of older ships, where the boilersneed replacement and a reboilering job is under consideration, newboilers are installed, which will generate the steam at higher pressure,which together with the higher temperatures, results in additionaleconomies. 1

Thus, many ships which still have serviceable hulls, but with mainengines of obsolete desi and which operate with a high fuel consumption,can be converted with my novel steam cylinders and with boilersuperheaters, to reduce the fuel consumption to an amount where they canbe profitably continued in service and in competition with modernturbine-propelled ships and other means of ship propulsion.

It is also practical and possible, with this de-' sign, to increase thehorsepower output of the oldengines up to the limit allowed by insuranceauthorities on the crankshaft and the propeller driving shaft, whichresults in increased speed of the ship. The increased speed givesadditional mileage, with increased revenues for freight and passengertransportation. This, in many cases, is of more value than the fuelsaving.

This design is not limited to conversion installations, but obviouslycan also be used on complete new ships and engines with more modernenclosed force-feed lubricated crankcases. It obviously also can be usedfor stationary in-.

stallations for power purposes, with the samev improvements in steam andfuel economies.

It is, accordingly, an object of my inventionto overcome the above andother limitations in my invention is to provide a.

inulti-cylinder steam engine with uniflow high pressure and unifiow lowpressure cylinders.

Another object of my invention is to provide a steeple-compound unifiowsteam engine which requires a minimum of head room.

Another object of my invention is to provide novel cooling means for thewalls of the highpressure cylinders of a steam engine.

Another object of my invention is to provide a compound steam engineoperating with high steam temperaturs, but with comparatively lower highpressure cylinder wall temperatures, and which can be safely andsparingly lubricated.

Another object of my invention is to relieve cylinder lubricationdifficulties in a steam engine operating with high-temperature steam.

Another object of my invention is to provide a novel poppet-valvemechanism for a steam engine with variable cutoff and other steamevents, desirable for maximum economy and with proper maneuverability.

Another object of my invention is to provide a steeple-compound enginein which the high-temperature. steam does not contact that portion oithepiston rod which enters the crankcase.

Another object of my invention is to provide a multi-cylindersteeple-compound engine, in which the reciprocating parts of allcylinders are identical and interchangeable and of equal reciprocatingweights, and in which the cylinders themselves are interchangeableduplicates, thereby reducing the number of spares which need to becarried and equalizing the reciprocating inertias, resulting in verymuch improved and smoother operation.

Another object of my invention is to provide a compound multi-cylindersteam engine which may be. adapted for use with any number of cranks andin which a complete steam cycle is carried through on each crank.

Another object of my invention is to provide high-pressure cylinders ina compound multic ylinder steam engine wherein exhaust steam issuingfrom the high-pressure cylinder to the low-pressure cylinder is utilizedto cool the cylinder wall of the high-pressure cylinder, thus permittingthe use of much higher initial steam temperatures.

Another object of my invention is to provide a steeple-compound enginein which both the high pressure and the low-pressure cylinders operateon the uniflow cycle, with attendant improved steam economies.

Another object of my invention is to utilize exhaust to cool thecylinder liners and walls of the high-pressure cylinder while passingthe steam to the low-pressure cylinder, and to utilize the heat soabsorbed in the steam to give useful work in the low-pressure cylinder.

Another object of my invention is to provide simple means, in asteeple-compound engine, where the lower cylinder is conventionallyinaccessible, for inspecting the condition of the lower or low-pressurecylinder walls and piston rings without dismantling, and to make the lowpressure piston packing rings replaceable through a removable bottomcover and without disturbing any other part of the engine.

Another object of my invention is to provide a steeple-compound uniflowengine which is opera'ble on high-pressure and high-temperature steamconventionally used only in steam turbine practice.

Another object of my invention is to provide novel-means for cooling thepistonrodpa-cking 4 disposed around the piston rod between thehighpressure and low-pressure cylinders in a steepletype compound steamengine with the lower temperature steam used in the low-pressurecylinder.

Another object of my invention is to provide novelmulti-steeple-compound cylinders with pistons and cylinder heads andpoppet-valves and inlet and exhaust manifolds, which may be adapted toand mounted on conventional open frames or columns now in use, and whichwill iitilize the existing cranks, connecting rods, crossheads, bedplatewith main bearings and shafting, and the conventional eccentric valvegearing, reversingmechanisms.,.etc., already assembled and in. use on.existing. ships.

Another object of my invention is to provide novelmulti-steeple-compound steam cylinders with a poppet-valve gear whichcan be actuated fromseiiis'ting conventional eccentrics and reversingmechanisms.

Another object of my invention is to minimize the horizontal distancebetween adjacent cylinder centerlines, which is governed by the diameterof the low-pressure cylinder, and thus gives a maximum totallow-pressure piston area for a given centerline-to-centerline dimensionon existing engines. This is accomplished in a single-actinghigh-pressure piston working with the pressure on the underside of thepiston on the upstroke, and a single-acting low-pressure piston workingwith the pressure on its upper side on the downstroke, and by utilizingthe upper side-of the high-pressure piston to complement thelow-pressure piston, both working on the downstroke.

Another object ofmy invention is to vent the underside of thelow-pressure piston continuously to the condenser, maintaining the lowtemperature of the vacuum steam throughout most of the low-pressurecylinder. Thus, the low-pressure cylinders can be bolted together and tothe columns of an open-frame engine, giving a rigid frame constructionover the tops of the columns, desirable for rigidity, and with a minimumchange in center-to-center horizontal dimension due to expansion, whichis important to maintain aligmnent with the crosshead guides and cranks.At the same time, all adjacent low-pressure cylinders bolted togetheroperate at very nearly identical temperatures, and expand verticallysmall and equal amounts.

In conventional open-frame compound tripleand quadruple-expansion steamengines, with double-acting cylinders, the high-pressure cylinde-rismuch hotter than its adjacent intermediate pressure or low-pressurecylinder and to which it is bolted, and expands a great deal more, bothhorizontally and Vertically. This resultsin severe stresses and muchmisalignment, which, due to this, further limits the steam temperatureswhich can be utilized on conventional engines. With my invention, thehorizontal dimension expands only that amount due to vacuum temperature,-125" F., and these dimensions are not affected in any way by theinitial steam temperature.

Another object of myinvention is to keep the reciprocating weights onall cranks equal, thus minimizing vibration and weaving of the columns,the bedplate and the cylinders, which is a serious objection to allconventional compound tripleand quadruple-expansion engines where-theweight of the low pressure piston far exceeds the weight of thehigh-pressure and intermediate-pressure pistons.

Another object of my invention is to increase the displacement of thelow-pressure cylinders, which governs the referred low-pressure meaneffective pressure in the cylinder. The greater the displacementthelower the mean effective pressure for a given horsepower and speed, andthe lower the mean effective pressure, the lower the steam rate perhorsepower. To illustrate, where the three cylinders of aconventionalitripleexpansion engine are replaced, the original enginehas one double-acting low-pressure cylinder, and in my invention itwould have three single-acting low-pressure cylinders of approximately50% increase in displacement. This further improves the economy, or itcan be utilized to increase the horsepower output and speed of an oldship.

Other objects of my invention will become evident from the followingdetailed description, taken in conjunction with the accompanyingdrawings, in which:

Fig. 1 is a side elevational view of my novel compound uniflow steamcylinders mounted on the columns of a conventional triple-expansionmarine engine and utilizing the eccentric valve gears of atriple-expansion steam engine to operate the poppet-valve gear of mynovel steam cylinders;

Fig. 2 is an end elevational View of my novel steam engine shown in Fig.1;

Fig. 3 is a top plan view of my novel steam engine shown in Fig. 1;

Fig. 4 is a sectional view taken on the line 44 of Fig. 3;

Fig. 4-a is a bottom view of the piston in the low pressure cylinder ofmy novel steam engine;

Fig. 5 is a fragmentary view showing the packing box engaging the pistonrod disposed between the high-pressure cylinder and the low-pressurecylinder of my novel steam engine;

Fig. 6 is a sectional elevational view taken on the line 6--6 of Fi 3;

Fig. 7 is a bottom View of the split end plates forming the lower coversof the low-pressure cylinders shown in Fig. 6;

Fig. 8 is a view taken on the line 8-8 of Fig. 6 with certain partsbroken away for better illustration; and

Fig. 9 is a fragmentary vertical sectional view taken on the line 99 ofFig. 2.

For purposes of illustration, I have shown my novel steam cylinders,cylinder heads and valve operating mechanisms mounted on conventionalvertical marine triple-expansion engine columns, although it will beevident that my novel cylinders, cylinder heads, manifolds and valveoperating mechanisms may be mounted on any type of conventional frame orcolumn with any number of cranks.

Referring now to the drawings, Figs. 1 to 11, inclusive, show a bedplateI, front columns 2, back or guide columns 2a, guide members 3,lowpressure cylinders 4, high-pressure cylinders 5, a crankshaft 6journalled in bedplate I, and connecting rods 1. Since each pair of highand lowpressure cylinders 5 and 4 constitute a complete compound engineor power unit, I will describe only one power unit. A piston rod I2 hasfixed thereon a high-pressure piston I3, operable in the high-pressurecylinder 5, and a low-pressure piston I5, operable in the low-pressurecylinder 4, and is pivotably connected to the connecting rod 1 by acrosshead I4 and a pin I I. I2 extends through an aperture I6 incylinder head I (Fig. intermediate the high-pressure cylinder 5 and thelow-pressurecylinde'r 4, and

The piston rod I passes through a flanged packing box I? extend ing intoaperture I6 and spaced from the sides thereof, in order that the packingbox I1 will be insulated from the high-temperature steam in the cylinderhead I0 and will be cooled by the low-temperature steam in thelow-pressure cylinder 4. As shown particularly in Figs. 4 and 6,. thelow-pressure cylinder 4 comprises a cylindrical member 20 with exhaustports 2I and an inwardly flanged portion 22, to which is attached splitsemi-circular plates 23, as shown in Fig. 7, by means of screw bolts 24.The flanged plates 23 have complementary depending flanged portions 25,which are secured together by bolt and nut assemblies 26, or by anyother suitable means. When the flanged plates 23 are secured together,an apertured portion 21 is formed centrally thereof to receive thepiston rod I2 and a flanged.

packing box 28. It will be evident that entrance to the lower end of thelow-pressure cylinder 4- may be attained at any time by merely removingthe plates 23.

The low-pressure piston I5 has an inverted L-shaped groove formed on thelower outer periphery thereof for nesting L-shaped rings I03 and packingrings I04 for sealing engagement with the inner wall of the cylinder 4.Segmental guide members I00 having soft-wearing metal pieces IOI arebolted to the underside of the piston I5 by means of capscrews I02 tosecure the L-shaped rings I03 and packing rings I04 in the.

groove in the piston I5. By removing the cap-- screws I02 and segmentalmembers I00, the L- shaped rings I03 may be dropped onto the flange: 22in the cylinder 4 and the packing rings I04 then may be renewed throughthe open bottom. end of the cylinder 4 after the plates 23 are re--moved.

In addition, inspection ports I05 are cast in the low-pressure cylinder4, opposite the ports 2I,, and these are covered with a removable plateI06 on the outside. By removing the plate I06 and by turning over theengine, the rings I04 will pass over these ports for inspection, and,

g at the same time, the entire interior of the lowpressure cylinder 4 isvisible for inspection through these ports I05 with no dismantling ofthe engine.

An exhaust chamber 29 is formed on the periphery of the cylinder 4outside of the exhaust ports 2|, and to this a suitable flanged exhaustpiping 30 is connected, leading to a condenser 3|. Base portion 32 ofthe cylinder 4 is flanged and seats on the upper ends of the columnmembers 2 and 211. I

The cylinder head I0 is secured to the upper end of the low-pressurecylinder 4, and has mounted on the upper side thereof and securedthereto, an inner sleeve 35, flanged outwardly at the bottom end thereofat 36, and an outer wall 37, spaced from the inner sleeve 35 to form thehigh pressure cylinder 5. The inner surface of the sleeve 35 ispreferably electro-porous chrome-plated to give a hard smooth surface onwhich the packing rings of high-pressure piston I3 may ride with aminimum friction.

The inner sleeve 35 has exhaust ports 38 circumferentiall thereof andspaced from the top end thereof by a distance equal to the verticalheight of the high-pressure piston I3, and which give an initial uniflowexhaust of the steam in the high-pressure cylinder 5 and under piston I3at the very top end of the stroke. This exhausted steam flows throughthe ports 38 into the annular chamber between the sleeve 35 and the'outi ton l3;

Theouter wall 31 is flanged outwardly at 39 to receive a flanged, domedhead 40, which. closes theupper end of the high-pressure cylinder 5. Theouter Wall 31, is flared outwardly intermedi+ ate thereofat 42, to formasteam chamber, and.

this is connected to steam line43, which inturn is connected to an openpassage 44in the.cylin.- they head If), which leads directly to theupper end of the low-pressure cylinder 4. It will thus be seen that thesteam freely passes from the high-pressure cylinder to the top. of1owpressure piston- I5 and the top of high-pressure piston [3 when. theyare both at the top of their stroke.

A high-pressure steam line 45, connectedwith a manifold 5|, is securedto the top surface of the cylinder head In diametrically opposite to thesteam line 43 and connects with a steam-chamber 46, the steam therebypassing from the chamber 46. upon opening of the poppet-valve4l intoport 4112, which is open to the high-pressure cylinder 4. Exhaust fromthe high-pressure cylinder 4 is continued after the pistons I3 and I5recede from the top of their stroke by opening poppet valve 48, whichconnects the port chamber 41a, open to the high-pressure cylinder 5,with a steam passage 50 leading to the upper end of low-pressurecylinder 4. Poppet-valve'52 is provided'in the cylinder head lfi toexhaust steam on the upstroke'of low-pressure piston I5 from passage 44,which is open to the upper'end of low-pressure cylinder 4, to a steamchamber 53, which passes the exhaust steam outwardly through passage 54and exhaust line 55, onsome cylinders directly to the exhaust line 36leading to the condenser 3|. On other cylinders, exhaust I line 55 isconnected to an exhaust manifold 56, which in turn is connected byextensions 51 and flanged joint 58 to aperture 59, opening intolow-pressure cylinder 4 under the low-pressure piston I5, and fromthence through ports 2I into manifold 30 leading to condenser 3 I.

In controlling the steam events in my novel steam engine, I utilizeexisting conventional eccentrics 69 on the crankshaft 6, havingeccentric rods 6i leading to conventional links 62, which in turn areconnected to valve rod 63, pivoted rocker arm 64, and adjustable linkrod 65. In some cases, the eccentric motion is carried by a rocker armIII) to a rock shaft III to an other rocker I I2, to which is pivotablyconnected adjustable link rod 65.

The valve rod 65 is pivotably connected to a double-armed rocker 66,which is adjustably mounted on a transversely extending camshaft 61,passing into camboxes I29 and I2ila mounted on low pressure cylinder 4on both sides of rocker 66. Each end of the camshaft 61 oscillates inflanged supporting bearings I21 bolted to the out- I20 and I2Ilav ofpoppet-waive 41 to reciprocate and open and closethis valve mountedinthe flanged cage I9.

To; the end of sleeve I2 4,,w ithin the cambox I20. (Fig. 4), is'bolteda. cam hub 8I concentric with. and adjustable on camshaft 61, and hassecured'thereon by screw bolt a cam member;

82. having a key portion 83, which engages. a. slotted. portion 84 invthe side of cam hub 8 I. The, rocker 86v is pivoted on shaft 'I5andcarries a, cam. roller 81 at its lower end, engaging the cam member 82'The upper end 88.0f the. rocker arm 85 engages, by means of tappet screw88a and. se.-.. cured by nut 88b, valve stem 89 of the large exhaustpoppet-valve 48, and reciprocates and opens and closes it in the flangedcage SI in which it is supported.

With reciprocation of valve rod 65'upwardly,

cam member 82 in cambox I26 will engage roller 81 of rocker 86, onwhose'upper end tappet screw- 38a will engage valve stem 89 openingvalve 48.- With reciprocation of valve rod 65 downwardly, valve 48 willbe closed and valve 41 will be opened.

The upper end of rocker arm 94 engages, by means oftappet screw 95secured by nut 9511, a

valvestem 96 of poppet valve 52 mounted inflanged cage 52a.

When poppet valves 41 and 52 are opened, theformer serves to admit steamunder the highpressure piston I3 on the upstroke and the latter toexhaust steam from the'low-pressure cylinder 5 above the low-pressurepiston I5, which will also be on its upstroke. The lift on exhaust valve52 will be less than that on admission valve 41, due to the short leverarm on rocker 94 as com- 7 pared with the long lever arm on rocker I4.

The exhaust valve 52 may be manually lifted independent of admissionvalve-41 for the purpose of venting the low-pressure cylinder 5continuously to the condenser for easy starting.

By proper disposition of the cam hubs and cam members in the camboxesI20 and I 20a bymeans of coupling flanges I23 and I23a, and by properproportioning of rockers 66 with the movement of the eccentric valvegear, proper steam events in the high and low-pressure'cylinders- 5 and4 may be obtained. Furthermore, any system of' eccentrics or any othertype of conventional reciprocating valve gear may be adapted for usewith my novel valve'mechanism, although I haveonly shown the adaptationto the use of the conventional Stephenson eccentrics and links of aconventional triple-expansion steam engine with my novel valvemechanism. All valves and themechanisms'therefor are independentlyadjustable, therefore providing for maximum efliciency.

In operation, high-pressure steam from the steam manifold 5[ passesthrough steam lines 45 to the steam chamber 46 in cylinder-head I0 andfrom thence through the poppet-valve 4I to the high-pressure cylinder 5.This high-pressure steam acts upwardly on the underside of piston I3 inthe high-pressure cylinder 5, and the steam is cut off at any suitablepredetermined point by-' proper adjustment of the cam hub 68-andcammember 69 controlling the poppet-valve 41. -I

When the piston I3 passes above the exhaust ports 38, steam passesoutwardly between the inner sleeve 35 and the outer wall 3! andequal-izes the pressure in the high-pressure cylinder with the pressureon top of the high-pressure piston I3 and in'the annular space betweensleeve 35 and outer wall 3! and through steam'line 43 and pas sage 44and with the-steam on top of low-pressure piston I5. Immediately afterstarting the down-- ward stroke, the ports 38 are again closed bypishigh-temperature ton I 3, but by this time the exhaust poppet-valve48 is open, thereby continuing the exhaust from the high-pressurecylinder through this valve into the low-pressure cylinder 4. Thiscylinder is permanently open through passages 44, steam line 43, and theannular space between liner 35 and outer wall 31 to the top of thehigh-pressure piston [3. Both high-pressure piston l3 and lowpressurepiston then continue the downward stroke, and when they have reached apredetermined portion of their stroke, the exhaust poppet-valve 48 isclosed. The piston I5 in the lowpressure cylinder 4, as it approachesthe bottom of the stroke, opens exhaust ports 2| and exhausts all of thesteam, both in low-pressure cylinder 4 and on top of high-pressurepiston l3 in high-pressure cylinder 5, to the exhaustline 30 and to thecondenser 3|. Thus it is apparent that the top of piston l3 inhigh-pressure cylinder 5 serves to give an additional low-pressuredisplacement complementing that of the main low-pressure piston l5. Thelow-pressure piston l5, after reaching the bottom of its stroke, beginsits upward stroke, and at a predetermined point in this upward movement,the low-pressure exhaust valve 52 is opened, continuing the exhaust tothe condenser through exhaust lines 55 and 56 to the exhaust manifold 30and the condenser 3 I. It will be evident upon inspection that propermovements and control of the poppet-valves 41, 48 and 52 may be obtainedby proper design of the cam members 69 and 82 and proper positioningrelative to the rocker arm 66.

It will be evident from the foregoin that I have provided a novelmulti-oylinder steam engine which may be utilized to convert any presentuneconomical, inefiicient steam engine into one which can efficientlyutilize high steam pressures and temperatures now prevailing in modernsteam practice. By permitting the lowtemperature steam of thelow-pressure cycle to pass freely on top of piston I3 within the sleeve35 and also between the sleeve 35 and the outer wall 37, this serves tokeep the temperature of the sleeve 35 in the high-pressure cylinder 5close to low-pressure cycle temperatures, and this temperature will bemuch below the initial high-temperature steam.

Also, the packing box I! surrounding the piston red I 2 between thehigh-pressure and lowpressure cylinders 5 and 4 is steam cooled bylow-pressure cycle steam within the low-pressure cylinder 4, therebymaintaining the temperature of the packing box I! at the temperature oflow-pressure steam and insulating it from the steam within the cylinderhead ID. The steam events in my novel steam cylinders are properly takencare of by the novel valve and cam arrangements which I have provided,and which may be adapted for use with any conventional bedplate andcolumns now in use with conventional eccentrics orany other type ofconventional reciprocating valve gear. The same patterns may be used forall high-pressure cylinders and for all low-pressure cylinders, and allthe cylinder heads therebetween, thereby greatly reducing the cost ofmanufacture.

My novel cylinder head and valve gear mechanism give accurate steamcontrol throughout the entire range of ahead and astern cutoffadjustments, provides ample port areas, automatic pressure release, andit permits the eiiicient use in a steam engine of high-pressure andhightemperature steam used in modern steam practice.

I have further provided a multiple-cylinder steam engine wherein thereis a direct and uninterrupted expansion of the steam from the cutoffpoint on the high-pressure upstroke to the unifiow exaust on thelow-pressure downstroke. The uniflow cycle used in both the highpressureand low-pressure cylinders provides an efficient exhaust for handlinginstantly large steam volumes. Passing of the exhaust steam through thecylinder head between the highpresssure and low-pressure cylinders,which contains steam of high initial temperature, is

thermally favorable on account of the reheating effect on the steamentering the low-pressure cylinder. The same thermally favorable effectis obtained by the heat removed from the highpressure sleeve 35. andwhich is utilized in the low-pressure cycle. Both cylinder barrels arecomparatively simple castings and simple to machine, which makes themquite different from the complicated cylinders and heads in conventionaldouble-acting engines, particularly of the multiple expansion type.

Due to the use of a short piston in both the high-pressure andlow-pressure cylinders, together with a single cylinder head placedbetween the two cylinders and serving both, the height or head roomrequired for my novel steam cylinders is only approximately 10% morethan that required by a double-acting unifiow engine of equal stroke,with its long piston and long cylinder and two cylinder heads, one aboveand one below.

With my novel engine, each pair of high pressure and low-pressurecylinders constitutes a complete compound engine and can, therefore,

be built in any number of double cylinders and can accommodate any crankrelations and gives balanced reciprocating weights. This diflers fromthe conventionaI double-acting compound triple or quadruple-expansionengine. The

compound must be built with 2 or 4 cylinders, the

triple-expansion engine with 3 or 4 cylinders, and thequadruple-expansion en ine with 4 or 5 cylinders. In each case the crankrelations are more or less fixed and the diameters are different on eachcrank, resulting in unbalanced weights. They also require thedevelopment of several different sizes of cylinder bores, all of whichcan be accomp ished with one development on my novel engine by varyingthe number of cylinders.

Valve operating mechanism for my novel mul 'tiple expansion steam engineis more particularly shown in my c'opending application for patent,Serial No. 28,612.

Various changes may be made in the specific embodiment of my invention,without departing from the spirit thereof, or from the scope of theappended claims.

What I claim is:

1. In a multi-cylinder steam engine, in combination, high-pressurecylinder and a lowpressure cylinder having admission and exhaust ports,valves for controlling the steam events in said cylinders, and an openauxiliary steam line between said high-pressure cylinder and saidlow-pressure cylinder.

- 2. In a multiple-cylinder steam engine, in combination, ahigh-pressure cylinder with double walls, a low pressure cylinder,valves for controlling the steam events in said cylinders, and an opensteam line between said low-pressure cylin- 23.1A multiple-cylindersteam engine .as -set forth in claim 2 wherein said double wall .infsaidhigh-pressure cylinderis open at the head end. 4. A multiple-cylindersteam engine as set iorth in claim 2 wherein said double wall, highpressure cylinder has exhaust ports in the inner wall thereof.

5. In a multi-cylinder steam engine, in combination, a high-pressurecylinder and a low-pressure cylinder, said high-pressure cylinder havingan inner sleeve spaced from the outer wall there- 6. A multi-cylinder.steam engine as set forth in claim ,5 wherein the space between saidinner sleeve and outer wall is open at the head end of the high-pressurecylinder.

7. A multi-cylinder steam engine as set forth .in claim 5 wherein aportion of the outer wall of said high-pressure cylinder is flaredoutwardly to form a steam chamber between said inner sleeve .and saidouter wall.

8. In a multi-cylinder steam engine, in combination, a high-pressurecylinder having inner and outer walls, a low-pressure cylinder, acylinder head between said high pressure and said low-pressure cylinderhaving a passageway'connecting the space between walls of saidhighpressure cylinder with said low pressure cylinder, valves in saidcylinder head, and means for ac- .tuating said valves to control thesteam events in field high-pressure and said low-pressure cyliners.

9. In a multiple cylinder steam engine as set forth inclaim-S wherein apiston rod in said cyl- ,1nders.is surrounded .by-a packing in saidcylinder head cooled by the steam in said low-pressure cylinder.

.10. A multi+cylinder steeple compound engine comprising a high-pressurecylinder, an inner sleeve in said high-pressure cylinder spaced fromtheouter wall thereof having circumferentially disposed aperturestherein, a low-pressure cylinider of the single-acting uniflow typedisposed belowsaid high-pressurecylinder, .a cylinder head disposedbetween said high-pressure and said low-pressure cylinder havingpassages for-admitting steam to said high-pressure cylinder, forexhausting steam from said high-pressure cylinder to saidllow-pressurecylinder,-and an open passage connecting the chamber'between saidsleeve'in "said high-pressure cylinder and the outer wall thereof andthetop of said low-pressure cylinder, valves in said cylinder head foropening and closing said admission and exhaust passages in said cylinderhead, and means for controlling said valves to control the steamevents'in said cylinders.

'11. A multi-cylinder steeple compound engine asset forth in claimwherein an exhaust valve and passage is provided'in said cylinder headto exhaust steam from said low-pressure cylinder.

12. A multi-cylinder steeple-compound engine as set'forth in claim 10wherein said low-pressure cylinder has inspection ports in the sidewalls thereof.

13. A multi-cylinder steeple compound engine comprising a high-pressurecylinder of the uniffiow type'having an inner apertured sleeve spacedfrom the outer wall thereof, a low-pressurecylin- 1:2 .der, a'cylinderhead disposed between said highpressure cylinder and said, low-pressurecylinder having an open passage, asteam line connecting thearea betweenthe inner sleeveand .outer wall of said high pressure cylinder, saidopen passage and .said low-pressure cylinder for passage of steamtherebetween, and means for controlling thesteam events in saidcylinders.

14. Amulti-cylinder steeple compound engine comprising ahigh-pressure-cylinder, a sleeve in said high-pressure cylinder havingcircumferentially spaced ports therein and spaced-from the top of saidcylinder, and from the outer 'wallof said cylinder, a low pressurecylinder of the uniflow type, a cylinder head having an open passagedisposed between said high-pressure and said lowpressure cylinder, asteam'line connecting the space between theinner sleeve and the outerwall of said high-pressure cylinder, said open passage in said cylinderhead, and 7 said low-pressure cylinder, and means for controlling thesteam events in-said cylinders.

.15. A multi-cylinder steeple compound engine comprising a high-pressurecylinder of the uniflow type having spaced walls, :the inner wall beingspaced from the top'of :said cylinder, a low pressure cylinder of thesingle-acting uniflow type, a'cylinder head having an open passage andadmission :and exhaust ports disposed between said high-pressure andsaid low-pressurecylinder, a steam line for connecting the space betweenthe walls of said high pressure cylinder, said open passage in saidcylinder head, and said low-pressure cylinder, valves in said cylinderheads for controlling the admission of steam to said high-pressurecylinder and exhaust steam from said high-pressure cylinder to saidlowpressure cylinder, and'means for actuating said valves to control thesteam events in said -cylinder.

16. A multi-cylinder steeple compound engine as set forth. in claim 15whereinan exhaust valve is disposed in said cylinder head for exhaustinsteam from said low-pressure cylinder.

17. A multi-cylinder steeple compound engine comprising a plurality ofhigh-pressure cylinders of the uniflow type, a plurality of low-pressurecylinders of the uniflowtype, cylinder heads between said high-pressurecylinders and said lowpressure cylinders having admission and exhaustportsyand an open passage,steam lines for connecting the high-pressurecylinders to said open passages in said cylinder heads and saidlowpressure-cylinders, admission valves and exhaust valves forcontrolling the admission and exhaust ports in said cylinder heads,exhaust valves for said low-pressure cylinders disposed in said cylinderheads, means for actuating said valves to control the steam events insaid cylinders, and selective means for actuating said exhaust valvesfor said low pressure cylinders.

18. A multi-cylinder steam engine comprising a double walledhigh-pressure cylinder of the unifiow type, a low-pressure cylinder ofthe uniflow type, valves for controlling the steam events in saidcylinders, and an open steam line between the chamber formed between thewalls of said high-pressure cylinder and said low-pressure cylinder.

19. A multi-cylinder steam engine as set forth .in claim 18 wherein theinner wall of said highpressure cylinder comprises an inner sleevespaced from the side and top of the outer wall thereof.

20. A multi-cylinder steam engine comprising a high-pressure cylinder, alow-pressure cylinder, a piston rod extending through said cylinders,pistons fixed on said rod in said high-pressure cylinder and saidlow-pressure cylinder, and an open steam line connecting saidhigh-pressure cylinder and said low-pressure cylinder and valves forcontrolling the steam events in said cylinder.

HERMAN G. MUELLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number 14 -UNITED STATES PATENTS Name Date Holloway Jan. 5, 1875 FidlerApr. 24, 1883 Brown Sept. 30, 1890 Heintzelman et a1. Mar. 22, 1892Player June 13, 1893 Raworth June 15, 1897 Prescott Jan. 27, 1903 JungNov. 12, 1912 Nickel et al July 15, 1913 Piquerez Dec. 11, 1924 SandersFeb. 15, 1938 Tabler Jan. 16, 1940 Houmoller July 22, 1941 Pelc Sept.15, 1942

